GPS Tracker Draining Your Car Battery? How to Fix It
Traknova
A flat battery after a few days parked is a serious operational problem, especially for rental fleets and leasing companies where vehicles sit unused between bookings. If you have ruled out a failing battery and the alternator is fine, a GPS tracker drawing too much current when idle is worth investigating.
How GPS trackers are supposed to behave when parked
A properly configured GPS tracker should enter a low-power sleep state within a few minutes of detecting that the vehicle is stationary. In sleep mode, a well-designed device draws between 5 and 20 milliamps. Most modern vehicles can tolerate a parasitic draw of up to 50 milliamps across all devices before the battery starts to struggle over a week.
A tracker stuck in high-power mode while parked can draw 80 to 200 milliamps continuously. Over 48 to 72 hours, that will flatten a standard 60Ah battery.
Most common cause: sleep mode not configured
Many trackers ship with sleep mode disabled or configured incorrectly. If the device never enters sleep, it runs at full power indefinitely, burning through the battery.
To fix this, access the device configuration and enable the sleep mode or power management setting. Most devices allow you to configure the trigger (motion sensor, ignition signal, or a timer) and the sleep depth (light sleep vs deep sleep).
Deep sleep uses less power but takes longer to wake. Light sleep wakes faster but draws more current. For fleet vehicles that need to be monitored while parked, light sleep with motion wake is usually the right balance.
OBD trackers: the OBD port does not always power off
OBD-connected trackers draw power directly from the OBD port. The problem is that many vehicles continue to supply power to the OBD port even when the ignition is off. The tracker never loses power and, if sleep mode is not configured, runs continuously.
Some OBD trackers also poll the vehicle’s ECU periodically to collect diagnostics data. Each poll wakes the vehicle’s CAN bus, which draws additional current. On some vehicles, particularly those with complex electrical systems, this can keep the ECU partially active for extended periods.
If you have an OBD tracker and a battery drain problem:
- Check whether the tracker has an ignition-detection setting and enable it.
- Enable aggressive sleep mode so the device reduces its polling frequency when parked.
- If the vehicle ECU remains active after the tracker is removed, there may be a separate issue with the vehicle itself.
Hardwired trackers: constant vs ignition power
Hardwired trackers are typically wired to one of two circuits: constant power (always on, even with the ignition off) or ignition-switched power (only powered when the ignition is on).
Most fleet trackers are wired to constant power so they can report while parked and detect theft. This is correct behaviour, but sleep mode must be properly configured to manage the draw.
A common installation error is wiring the tracker to ignition power when the configuration expects constant power, or vice versa. If the tracker is wired to ignition-switched power, it powers off completely when the vehicle is parked, which means no tracking while stationary but also no battery drain.
What suits your fleet depends on whether you need to monitor parked vehicles. For taxi, rental, and leasing fleets, constant power with sleep mode is the right setup.
OBD vs hardwired: a quick comparison
| OBD tracker | Hardwired tracker | |
|---|---|---|
| Installation | Plug in, no tools | Requires fitting |
| Power source | OBD port (always live on most vehicles) | Wired to constant or ignition circuit |
| Sleep mode | Device dependent | Device dependent |
| Battery drain risk | Higher if sleep mode not configured | Manageable with correct config |
| Removal by driver | Easy | Difficult |
For fleet management where battery drain is a concern and removal by drivers is a risk, a hardwired installation with properly configured sleep mode is the better choice.
Step-by-step fix sequence
- Confirm the tracker is the cause: remove it for 48 hours and see if the battery drain stops.
- Access the device configuration and confirm sleep mode is enabled.
- Set the sleep trigger to motion detection or ignition signal.
- For OBD devices, check whether ignition detection is available and enabled.
- Review the ECU polling frequency settings if accessible.
- If the device does not support adequate sleep mode, consider replacing it with a model that does.
Get the right setup from the start
Traknova’s GPS tracking platform supports a range of hardware with proper sleep mode configuration built in. If you are fitting trackers across a fleet and want to avoid battery drain issues, book a demo and we can walk through the right device and configuration for your vehicle types.